<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>

        /* 最小为600px宽得布局 */
        @media all and (min-width: 800px){
            div{
                background-color: #f00;
            }
        }
        /* 最大单为700px的布局 */
        @media all and (max-width: 600px){
            div{
                background-color: #0f0;
            }
        }

        @media all and (min-width: 600px) and (max-width: 800px){
            div{
                background-color: #00f;
            }
        }
    </style>
</head>
<body>
    <div style="width:200px;height:200px">响应式布局</div>
</body>
</html>